Google suffered a massive Gmail outage last night that affected up to 10 percent of its global users, leaving them unable to access their personal email accounts --- and in some cases, their work email.

The outage began at 12:42 p.m. EDT on Tuesday and lasted for more than an hour. While many Gmail and Google Apps users in the U.S. were left without access, it appeared that the UK, Europe, and Asia remained mostly unscathed by the outage.

Google initially said the outage affected less than 2 percent of the Gmail user base, with the estimated 5.3 million affected users "unable to access Google Mail". Half an hour later at 1:46 p.m. EDT, Google said that the problem "should be resolved".

Later in the evening, Google hiked the figure and said the problem had caused "less than 10 percent" of its user base were left without their email.

The company noted on its Google Apps Dashboard: "it's possible that some users may experience message delays because affected accounts weren't available to receive messages. The messages will be successfully delivered after account access is restored."

Reports suggest that only the web interface was affected by the outage, while those using IMAP/POP connections in a third-party desktop client, or mobile users, could still access their accounts and email.

The web giant achieved 99.984 percent uptime last year, according to its internal statistics, which stormed ahead of cloud computing competitor Microsoft, after the Redmond-based company suffered a series of high-profile outages of its own.

It came only a few days after the UK's advertising authority initiated an investigation into the claims Microsoft made about its cloud service reliability. The company has been quick to explain why many of its outages occurred, but nevertheless left many Office 365 customers without email or communications for periods of half-days at a time.